The somatoform disorders were first delineated as a class of psychiatric disorders in DSM-III (American Psychiatric Association 1980). The class was created to facilitate the differential diagnosis of disorders characterized primarily by "physical symptoms suggesting physical disorder (hence somatoform) for which there are no demonstrable organic findings or known physiological mechanisms and for which there is positive evidence, or a strong presumption, that the symptoms are linked to psychological factors or conflicts" (American Psychiatric Association 1980, p. 241). With minor modifications, this grouping and its underlying concept were retained in DSM-III-R (American Psychiatric Association 1987) and, after some debate (Martin 1995), in DSM-IV (American Psychiatric Association 1994) as well as DSM-IV-TR (American Psychiatric Association 2000). (Noteworthy here was that the explicit diagnostic criteria from DSM-IV remained the same in DSM-IV-TR.) In contrast to factitious disorders and malingering, somatoform disorder symptoms are not under voluntary control. The stipulation in DSM-IV-TR that symptoms are not fully accounted for by known physiological mechanisms distinguishes somatoform disorders from disorders formerly designated as psychophysiological disorders, some of which are included in DSM-IV-TR under "Psychological Factors Affecting Medical Condition." Beliefs involving preoccupations with symptoms are not of delusional intensity, except possibly for body dysmorphic disorder. Symptoms are not better accounted for by other mental disorders.